KR101756323B1 - Method of Building a Hybrid Tower for a Wind Generator - Google Patents

Abstract

In the hybrid tower construction method according to the present invention, the metal mast 4 is erected and connected to the base 11, and a concrete structure 3 is constructed around the metal mast using a metal mast as a support. The metal mast is then removed from the base and lifted by telescoping and guiding the metal mast along the concrete structure. Finally, the lifted metal mast is connected to the concrete structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a hybrid tower for a wind turbine generator,

The present invention relates to the construction of a hybrid tower having a bottom made of concrete and a top made of metal.

Typically, such towers are used to support a nacelle of coastal wind power generators with large power (eg, greater than 3 MW) towering above the ground (eg, about 140 m).

As the height of the wind turbine tower increases, the cost of the conventional cylindrical steel mast is too high. To circumvent the technical limitations of the cylindrical metal mast, some manufacturers have developed towers made of steel trellis (or truss). However, these towers are not good for aesthetic view.

Other manufacturers use climbing or sliding dies to build concrete pits on at least a portion of the tower's height. This type of construction method is sensitive to the temperature conditions that can be experienced in the field, so that the coagulation of the concrete is slow or accelerated and is also sensitive to wind conditions because the concrete temporary frame must be mounted as a tall crane. This construction method is very expensive for very high towers.

Some wind turbine towers are made of pre-fabricated concrete elements over the full height. The elements are lifted using a toll crane. The elements can be assembled into an annular segment on the ground, and the crane is strong enough to lift the entire segment or directly into a high segment position. The disadvantage of this technique is that it is sensitive to wind-related constraints and has a significant impact on construction delays. Another limitation is the availability of crane with sufficient power and height, which must be booked in advance a few months in advance.

Several telescoping technologies have also been proposed for the construction of wind farms. For example, DE 10111280 discloses a wind power plant in which a mast segment is lifted by a lift device and a new segment is inserted beneath it. JP 1 190883 discloses a method of lifting a steel tower at the top of a tall building using a balance weight and jack fixed to the bottom of the tower. Another device for lifting wind turbine assemblies is disclosed in WO 2007/125138 A1.

A hybrid tower made of concrete at a portion of height (for example, 50 m or more) and an industrial concrete process in the concept of a metal mast at the top of the tower eliminates the need for a civil engineer to handle a heavy load using a large capacity crane . This technique is compatible with a wind turbine generator with its own crane installed with nacelle. However, this technique is difficult to implement in practice.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is a main object of the present invention to further develop the concept of a hybrid tower so that it becomes more practical.

In order to achieve the above object,

Establishing a metal mast connected to the base;

Constructing a concrete structure having a plurality of overlapping concrete segments around the metal mast using a metal mast, such as a support,

Separating the metal mast from the base,

Lifting the metal mast by telescoping and guiding the metal mast along the concrete structure;

And a step of connecting the lifted metal mast to the concrete structure.

The step of constructing the concrete structure

a) installing at least a first segment of the concrete structure,

b) lifting the installed segment (s) of the concrete structure along the metal mast to receive the next segment of the concrete structure by arranging the space of sufficient height by guiding the lifted segment of the concrete structure using a metal mast,

c) installing a next segment of the concrete structure in the space,

d) repeating step b) and step c) until the last segment of the concrete structure is installed at the lower end of the concrete structure.

The metal mast is used as a support in the construction of the concrete structure, and the concrete structure is then used as a support for raising the metal mast. The method is suitable for industrial installation of large wind farms and many steps are performed on the ground where environmental conditions are better adjusted or controlled.

Concrete structures are generally constructed by assembling pre-fabricated elements, but at least a portion of the height of the concrete structure may also be used for field casting methods.

In one embodiment, a guide structure is connected to the lower end of the metal mast, and the guide structure has a lower portion formed with a guide for cooperating with the concrete structure when the metal mast is lifted. The guide structure is detachably connected to the lower end of the metal mast and can be separated after the step of lifting the metal mast and reused to build another tower.

The guide structure can be used as a lifting support structure in the step of constructing the concrete structure, with the guide structure disposed between the metal mast and the foundation in the stage of building the metal mast.

Effects of the hybrid tower construction method for a wind turbine according to the present invention will be described as follows.

First, there is an advantage of producing concrete segments on the ground.

Secondly, the guide structure of the present invention is also advantageously used as a lifting support structure for guiding and stabilizing the mast in the concrete structure construction stage.

Other features and advantages of the methods and towers disclosed herein will become apparent from the following non-limiting examples with reference to the accompanying drawings.
1 is a schematic perspective view of a wind turbine installed at an upper end of a hybrid tower.
Figures 2-6 illustrate various construction steps of a hybrid tower in an embodiment of the present invention.

As shown in Fig. 1, a hybrid tower 1 for a wind power generator 2 has a concrete structure 3 at the bottom and a metal mast 4 at the top. A nacelle (5) for a generator (2) is mounted on the upper end of the metal mast (4). The metal mast 4 may be made of one or more cylindrical steel sections assembled by bolting and welding.

In the illustrated embodiment, the concrete structure 3 comprises overlapping segments 6 that are assembled in situ from pre-fabricated concrete elements. The concrete structure 3 is generally conical, and a certain angle may be formed above the height of the concrete structure 3. If the distance between the tower wall of the wind generator 2 and the rotating blade 7 is desired to be constant, it may also have a cylindrical concrete section on the cone. In the example shown in Fig. 1, the cone has a circular base. It is understood that various other shapes, e.g., pyramidal shapes with a constant angle, can be used, which can minimize the number of molds for molding the concrete elements.

To construct the hybrid tower, a foundation (not shown in FIG. 1) is laid first on the ground. The bars may be a deep base that extends deep into the ground, or it may be an apparent foundation with sufficient inertia and horizontal expansion to stabilize the tower. The steel mast 4 is then raised and firmly connected to the base of the base to be used as a supporting structure in the construction of the concrete structure 3. Once the concrete structure is complete, the metal mast is separated from the base and lifted by telescoping and guiding along the concrete structure. At the end of the lifting stroke, the steel mast 4 is connected to the top of the concrete structure 3.

The concrete structure 3 can be constructed by lifting pre-manufactured concrete elements by using a crane or a winch mounted on the upper end of the mast 4 and superimposing the concrete elements on the structure. The central mast 4 is used as a support for lifting and / or positioning elements particularly useful when blowing.

In another embodiment shown in Figures 2-5, the concrete structure 3 is constructed by assembling the segments from bottom to top. Each segment 6 can be manufactured by assembling the concrete elements at the ground and overlaying the elements along a vertical joint. It is advantageous to produce concrete segments at the ground because it is relatively easy to control the environmental conditions by forming an enclosure to protect the working area from the wind and ensure adequate temperature if necessary.

As shown in FIG. 2, a support structure 10 is disposed between the metal mast and the base 11 when the metal mast is erected. In the illustrated example, the support structure 10 includes a horizontal platform 12 for the mounting jack used in the lifting step, a lower frame 13 between the base 11 and the platform 12, 4 between the bottoms of the frames. The frames 13 and 14 are made of, for example, a steel trellis (or a thrust).

2 shows the first segment 6 of the concrete structure 3 located at the top of the concrete structure 3 when the construction is finished. This segment 6 is formed by assembling a number of pre-fabricated concrete structures carried out using guide rails laid on the ground or by placing the concrete in a form arranged on a foundation 11 around the lower frame 13 of the support structure 10. [ ≪ / RTI > When the first segment 6 is completed, the bracket 16 has a horizontal mating face 17 for receiving the lower end of the hoisting cable. Many (e.g., eight) brackets 16 are distributed along the circumference of the segment 6. Each hoist cable 18 extends beyond the platform 12 of the support structure 10 where the jack 19 is held.

From the position shown in Figure 2, the jack 19 is pressed to pull the hoist cable 18, thus lifting the segment 6 and building it directly. The segment 6 is moved to the position shown in the upper part of Fig. Figure 3 also shows a guide member 20 positioned between the inner surface of the first segment 6 and the outer surface of the cylindrical steel mast 4. These guide members 20 may be fixed to the segments 6 and the innermost end of the guide members may have rollers held against the mast 4. Guides and stabilizes the concrete structure (3) while the plurality of guide members (20) are constructed distributed along the circumference of the segment (6). The guide member can be fixed inside the segment 6 by the driver in the platform 12 after the segment 6 is fully raised. Alternatively, each position of the guide member is offset relative to each position of the jack 19 and is fixed when the segment 6 is in the lower position shown in Fig.

With the first segment 6 in the raised position shown in Fig. 3, the next segment 6 can take the concrete element as indicated, for example, by the arrow B and be assembled underneath as a fold over. When this next segment 6 is ready, the jack 19 is gradually released to slowly lower the previous segment 6 on the top surface as indicated by the arrow C. Adhesives are placed on the interface between the two adjacent segments (6) to overlay them if necessary.

At this time the jack 19 is controlled to lower the hoist cable 18 and attached to the inner surface of the assembled segment 6 immediately after the bracket 16 is released (possibly after being released from the previous segment) And the lower end of the cable 18 is attached to the mating face 17 of the bracket 16, respectively. The jack 19 is then pressed again to lift the two assembled segments 6 as indicated by arrow D in Fig. During this lifting process, the concrete structure 3 is properly guided along the mast 4 by the guide member 20.

Thereafter, the sequence of operations of Figs. 3 and 4 is repeated several times until all the segments 6 of the concrete structure 3 are installed. Optionally, additional guide members, such as 20, may be installed in the one or more segments 6 to further improve the stability of the concrete structure 3.

After the last segment 6 (the segment at the bottom of the tower) is located, prestressing cables, for example, using the process described in patent application EP 09306323.8, filed December 23, 2009 So that the concrete structure 3 can be reinforced.

Then the steel mast is lifted. Again, this lifting can be performed using the platform 12 of the support structure 10 and the cable jack. This is done after detaching the lower frame 13 of the support structure 10 from the base 11. [

In the embodiment shown in Figure 5, an annular plate 25 is disposed at the top of the concrete structure 3. The annular plate 25 has a central hole that leaves openings for the steel mast 4 during lifting and apertures that are regularly distributed along the perimeter of the passageway, but the wall of the concrete structure (if the concrete structure is high) Retains the upper end of a long housing cable 28 therein. The lower end of the long housing cable 28 is connected to a respective jack 29 held on the lower surface of the platform 12. The jack 29 is pressed to raise the platform 12 and an element to be secured to the platform including the frame 13,14 and the steel mast 4 of the support structure 10, do.

During the lifting of the steel mast 4, a pre-stressed concrete structure 3 was built in advance and is used as a support to guide and stabilize the mast 4, if necessary. The guide member 20 (Figs. 2 and 3) located near the top of the concrete structure 3 includes not only the steel mast 4 but also any additional guide members, which can be attached to the inner surface of the concrete segment 6 during erection, The concrete structure 3 can be guided again.

For the guiding function of the concrete structure 3, an important step is obviously the last stage in which the mast 4 reaches its final position on the concrete structure 3. The guide efficiency is proportional to the vertical distance between the highest and lowest fulcrums and the distance is minimized during the final stage and also the effect of wind is greatest.

In order to enhance the guide function, the above-mentioned vertical distance is increased by using an additional guide member 30 attached to the lower part of the lower frame 13 of the support structure 10. [ These guide members 30 are distributed around the outer periphery of the lower frame 13 in the constellation (star image) arrangement. Each of which includes a fixed arm 31 attached to the lower frame 13, a movable arm 32 that can slide radially away from the lower frame 13 at the end of the fixed arm 31, (Not shown) for controlling the radial expansion of the movable arm 32. The roller 33 is pivotally mounted around the horizontal axis at the end of the movable arm 32,

The guide member 30 is attached to the support structure 10 before actuating the jack 29 to lift the mast 4. At this time, the movable arm 32 extends outward so as to be attached to the inner wall of the concrete structure 3. When the mast is raised, the position of the movable arm 32 is adjusted by the actuator to gradually contract, thereby reducing the cross-section of the concrete structure 3 in front of the guide member 30. [

The nacelle 5 of the wind power generator 2 may be installed at the top of the mast 4 after the telescoping operation. Alternatively, the nacelle is installed before the mask extends or after the mast is partially extended. In this case, it is preferable that the gravitational center of the nacelle is aligned at or near the center axis of the tower.

Figure 6 shows the position of the mast 4 and the support structure 10 at the end of the lifting operation. The left portion of the drawing shows the angular position with the guide member 20 while the right portion shows the angular position with the hoist cable 28 and the connecting jack 29. The vertical distance H between the guide member 20 near the upper end of the concrete structure 3 and the guide member 30 at the lower end of the support structure 10 is smaller than the distance h between the guide member 20 and the lower end of the mast It seems to be considerably much larger. Thus, the support structure 10 is designed as a guide structure which contributes to stabilize the mast 4 prior to final connection to the concrete structure 3. Advantageously, the guide structure 10 is also used as a lifting support structure in the construction of the concrete structure 3, which is also referred to with reference to Figs. 2-4.

The arrangement of the guide / support structure 10 different from the arrangement shown in Figs. 2-6 can be considered. In one such arrangement, the structure 10 has a second movable platform connected to the fixed platform 12 by a hoist cable 18 and capable of sliding along a vertical rail. The movable platform is attached to the lower end of the segment (6) for lifting from below when assembling the concrete structure (3). And a guide member 30 is provided at a side edge thereof for use in the step of lifting the steel mast 4.

Various means for connecting the steel mast 4 to the concrete structure 3 can be used singly or in combination. For example, a steel beam can be horizontally inserted into an area where the lower part of the mast 4 overlaps the upper part of the concrete structure 3. It is also possible to provide a first temporary frame on the steel mast 4 projecting outward from the bottom of the metal mast and a second temporary frame on the concrete structure 3 projecting inwardly from the uppermost segment 6, The first and second temporary frameworks can be extended and poured into the overlapping space with cement or mortar to connect the lifted metal mast to the concrete structure.

The guide structure 10 is then disconnected from the lower end of the metal mast 4 and can be lowered to the foundation height using the cable 28 and the jack 29 have.

It will be understood that the above-described embodiments are examples of the invention disclosed herein, and that various modifications may be made without departing from the scope of the invention and the scope of the claims. For example, a concrete structure of many elements can be assembled using a crane before installing other elements according to the method described with reference to Figs. 2 to 4.

1: Hybrid tower 2: Wind generator
3: Concrete structure 4: mast
5: Nacelle 6: Segment
7: rotating blade 10: supporting structure
11: Foundation 12: Fixed Platform
13: lower frame 14: upper frame
16: Bracket 17: Horizontal mating face
18: hoist cable 25: annular plate
8: Cable 29: Jack
20, 30: guide member 31: stationary arm
32: movable arm 33: roller

Claims (6)

A metal mast (4) connected to the base (11)
Constructing a concrete structure (3) having a plurality of overlapping concrete segments (6) around the metal mast using a metal mast, such as a support,
Separating the metal mast from the base,
Lifting the metal mast by telescoping and guiding the metal mast along the concrete structure;
A method of constructing a hybrid tower (1) having a step of connecting a lifted metal mast to a concrete structure,
The step of constructing the concrete structure
a) installing at least a first segment (6) of the concrete structure (3)
b) guiding the lifted segment (6) of the concrete structure along the metal mast (4) using a guide member (20) located between the metal mast and the segment to accommodate the next segment of the concrete structure Lifting the installed segment (s) of the concrete structure along the metal mast (4)
c) installing a next segment of the concrete structure in the space,
d) repeating step b) and step c) until the last segment of the concrete structure is installed at the lower end of the concrete structure. The method according to claim 1,
The concrete structure (3) is constructed by assembling pre-fabricated elements. 3. The method according to claim 1 or 2,
Further comprising the step of mounting a wind power generator nacelle (5) on top of the metal mast (4). The method according to claim 1,
The guide structure 10 is connected to the lower end of the metal mast 4,
Wherein the guide structure has a lower portion formed with a guide for cooperating with the concrete structure (3) when the metal mast is lifted. 5. The method of claim 4,
The guide structure (10) is separated from the lower end of the metal mast (4) after the step of lifting the metal mast. The method according to claim 4 or 5,
A guide structure 10 is disposed between the metal mast 4 and the base 11 in the step of raising the metal mast and the guide structure is used as a hybrid tower construction used as a lifting support structure in the step of constructing the concrete structure 3 Way.

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